Supply high quality microbiological studies for the care of cancer patients who receive chemotherapy at the Baltimore Cancer Research Center (BCRC) and the Pediatric Oncology Branch (POB), Division of Cancer Treatment, National Cancer Institute (DCT, NCI). Data obtained by means of this contract will provide specific identification of the infecting microorganism to enable the use of optimal therapy, disclose the patients' endogenous flora (present at admission and hospital acquired), allow monitoring of sources of hospital acquired infection, and provide the basis for evaluation of protective environments for immunosuppressed patients.